Here's how Chinese government officials have the freedom to blog, against all intuitive expectations. The government doesn't ban sites: it blocks data that includes banned words.

Science Daily puts it this way.

The "Great Firewall of China," used by the government of the People's Republic of [tag]China[/tag] to block users from reaching content it finds objectionable, is actually a "panopticon" that encourages self-censorship through the perception that users are being watched, rather than a true firewall, according to researchers at UC Davis and the University of New Mexico.

As they say, "Many countries carry out some form of Internet [tag]censorship[/tag]."

And in the USA, the University of Arizona catalogues and studies places online where terrorists operate. That's more than 5,000 web sites. The techniques they use are complex and fascinating and include one that amounts to fingerprinting content:

One of the tools developed by [tag]Dark Web[/tag] is a technique called Writeprint, which automatically extracts thousands of multilingual, structural, and semantic features to determine who is creating 'anonymous' content online. Writeprint can look at a posting on an online bulletin board, for example, and compare it with writings found elsewhere on the Internet. By analyzing these certain features, it can determine with more than 95 percent accuracy if the author has produced other content in the past. The system can then alert analysts when the same author produces new content, as well as where on the Internet the content is being copied, linked to or discussed.